Observation of charged excitons in hole-doped carbon nanotubes using photoluminescence and absorption spectroscopy

TL;DR

This paper reports the first observation of trions in hole-doped carbon nanotubes at room temperature, revealing large energy separations due to strong exchange interactions, using photoluminescence and absorption spectroscopy.

Contribution

It provides the first experimental evidence of trions in hole-doped carbon nanotubes at room temperature, highlighting the role of exchange interactions.

Findings

Trions appear far below the E11 exciton peak in doped nanotubes.

The energy separation between excitons and trions is unusually large.

Trions are observed regardless of the dopant species.

Abstract

We report the first observation of trions (charged excitons), three-particle bound states consisting of one electron and two holes, in hole-doped carbon nanotubes at room temperature. When p-type dopants are added to carbon nanotube solutions, the photoluminescence and absorption peaks of the trions appear far below the E11 bright exciton peak, regardless of the dopant species. The unexpectedly large energy separation between the bright excitons and the trions is attributed to the strong electron-hole exchange interaction in carbon nanotubes.